[Evaluation of retinal microvascular characteristics in Leber hereditary optic neuropathy based on optical coherence...

Objective: To evaluate retinal microvascular characteristics in patients with Leber hereditary optic neuropathy (LHON) by optical coherence tomography angiography (OCTA). Methods: The LHON patients diagnosed with 11778G>A mutation in the Department of Neurology, Beijing Tongren Hospital, Capital Medical University from August 2022 to August 2024 were retrospectively collected. Family members of the patients and hospital staff were recruited as healthy controls during the same period. LHON patients were divided into group A (asymptomatic stage), group B (subacute stage), group C (dynamic stage) and group D (chronic stage) according to the course of disease. OCTA images were used to compare the macular microvascular characteristics of each group, and the correlation between visual impairment and the blood flow parameters and structural parameters was analyzed. Results: A total of 21 LHON patients with 42 eyes and 15 healthy controls with 30 eyes were included. There were 5 eyes in group A , 11 eyes in group B , 10 eyes in group C, and 16 eyes in group D. The ages of LHON patients and healthy controls were (24.2±4.0) years and (24.3±3.9) years, respectively. The duration of disease in group B, C and D were (3.1±1.4) months, (9.6±1.2) months and (16.4±3.4) months, respectively. The Logarithm of the minimum Angle of Resolution (LogMAR) of best corrected visual acuity (BCVA) in LHON patients (1.30±0.76) was higher than that in the healthy control group (0) (P<0.001). When macular perfusion density (PD) and blood flow length density (VLD) in LHON patients were compared with those in healthy controls, nasal PD and VLD in group A (P=0.034 and P=0.044), the average value, nasal and inferior PD and VLD, and superior VLD in group B (P<0.05) , and the average values of PD, VLD and macular areas in groups C and D were lower than those in the healthy control group (P<0.001). The thickness and average value of the general ganglion cell complex (GCC) in all regions of the macular in the LHON group were lower than those in the healthy control group (P<0.05). The temporal and inferior peripapillary retinal nerve fiber layer (pRNFL) thickness and average value in group A were thicker than those in the healthy control group (P<0.05). The temporal pRNFL thickness and average value in group B were lower than those in the healthy control group (P<0.001). The average pRNFL thickness and all regional thicknesses in C and D groups were lower than those in healthy controls (P<0.001). The BCVA LogMAR was negatively correlated with all blood flow parameters and structural parameters (r=-0.744--0.969, P<0.001). Among blood flow parameters, the correlation between BCVA LogMAR and VLD (r=-0.881--0.900) was relatively strong. Conclusions: The macular microvascular impairment in LHON patients gradually increases with the progression of the disease. The visual impairment is correlated with both the blood flow parameters and structural parameters of OCTA, and early macular microvascular changes suggeste poor visual prognosis.